I would start by seeing if your ISP has a list of supported models. Pretty sure satellite must use the provider's modem. Cable service is often picky, if that's what you have. DSL less so. (And I assume you're not on dialup.)
Fixed wireless, PPPoE, and fiber should all be giving you an Ethernet handoff so you shouldn't need a modem for those. And if somehow you still have a T1 line, god help you.